It is possible to keep glofish with bettas, but glofish are schooling fish and need to be in groups of at least 3 ore more with plenty of room to swim. In the past, I have kept a group of glofish with a single male betta in a 20 gallon. Honestly, the glofish seemed to annoy him.... although they did not nip his fins. It depends on the fish and how your tank is set up I guess. I do think glofish are less aggressive than regular zebra danios.